Pressing tool

ABSTRACT

The invention relates to a pressing tool ( 8 ) provided with three or four press mandrels ( 12, 15 ) which move towards each other during the pressing process. The press mandrels ( 12–15 ) have a roof-shaped transversal profile. The lateral distance ( 36 ) between the press mandrels ( 12–15 ) is increasingly reduced during the pressing process. An extending element ( 37 ) is arranged between two press mandrels, extending from one press mandrel to another press mandrel and being inserted into the other press mandrel during the pressing process. The aim of the invention is to improve said pressing device and to improve pressing. In order to block the above-mentioned distance ( 36 ), the extending element ( 37 ) is disposed in such a way that both roof edges ( 38 ) of the corresponding press mandrels cut across said extending element ( 37 ) in an initial position.

This application claims priority with respect to German Application No.10100398.6, filed Jan. 5, 2001, and PCT Application No. PCT/EP01/14063,filed Dec. 1, 2001.

The invention relates, in the first instance, to a pressing tool withthree or four pressing mandrels which can be moved towards one anotherduring a pressing process, it being the case that the pressing mandrelshave a roof-like cross-sectional profile, and that, furthermore, alateral clearance space between the pressing mandrels is increasinglyreduced during a pressing process, and disposed between two pressingmandrels is an extension element which extends from one pressing mandrelto the other and moves into the other pressing mandrel during pressing.

Such pressing tools are known and serve, inter alia, for connecting acable end to a cable eye, two or three of the pressing mandrels beingdisplaced, by means of hydraulic actuation, in the direction of thecentre of the pressing space during the pressing process. In thisrespect, for example, a four-mandrel pressing tool is known fromCanadian patent 679 495 which has a fixed pressing mandrel and threefurther pressing mandrels which can be displaced to the centre of apressing space, in each case one extension element being disposed in theregion of the lateral clearance spaces between the displaceable pressingmandrels, for the purpose of guiding the pressing jaws carrying thepressing mandrels. The problem with the known pressing tools is that,between being placed in position and actually being pressed, the blank,for example the cable eye accommodating a cable end, changes itsposition to the extent where unsuccessful pressing is achieved.

In respect of the abovedescribed prior art, it is a problem of theinvention for a pressing tool of the type in question to be developed inan advantageous manner in particular in respect of an improved pressingresult.

This problem is solved first and foremost by the subject matter of claim1, this being based on the fact that the extension element, for thepurpose of blocking the clearance space, is arranged such that, in theinitial state, the two roof edges of the associated pressing mandrelscut across the extension element. As a result of this configurationaccording to the invention, the blank which is to be placed in positionand pressed is supported at such a level that, as the pressing mandrelsare moved towards it, self-centring of the blank between these mandrelsis achieved. The pressing sleeve of a cable eye is thus always locatedentirely in the region of action of the pressing mandrels, so thatprecise, successful pressing of the cable eye and cable end is alwaysachieved. The extension element here is positioned such that a blankwhich is not positioned centrally in the pressing space is always forcedinto the desired pressing position by the extension element during thepressing process. In this case, an extension element is disposed betweentwo pressing mandrels such that the respectively facing edge of thepressing mandrel, at least in prolongation of the same, cuts across theextension element. Furthermore, the arrangement of the extension elementis selected such that the blank which is to be pressed, in an originalarrangement in the region of the lateral clearance space between twopressing mandrels, encloses an angle, between a perpendicular to thedirection in which the blank is advanced out of the clearance space anda bearing point on an oblique surface of a pressing mandrel, which islarger than the angle of friction, this achieving the desiredadvancement of the eccentrically positioned blank between the pressingmandrels during pressing. In a preferred configuration, extensionelements disposed according to the invention pass through two of thethree lateral clearance spaces, in a pressing tool with three mandrels,and through three of the four clearance spaces, in the case of apressing tool with four pressing mandrels.

It may also be provided that the fixed pressing mandrel is fastened on apivoting bracket, by means of which the radial access to the pressingspace can be blocked. Following placement and closure of the pivotingbracket, the latter is preferably locked in a positive manner. In orderto achieve an improved pressing result, in the case of a four-mandrelpressing tool of the type in question, it being the case that thepressing mandrels have a roof-like cross-sectional profile, and that,furthermore, a lateral clearance space between the pressing mandrels isincreasingly reduced during a pressing process, and disposed between twopressing mandrels is an extension element which extends from onepressing mandrel to the other and moves into the other pressing mandrelduring pressing, it is proposed that the extension element, for thepurpose of blocking the clearance space, is disposed such that, in theinitial state, the two roof edges of the associated pressing mandrelscut across the extension element. As a result of this configurationaccording to the invention, the blank which is to be placed in positionand pressed is supported at such a level that, as the pressing mandrelsare moved towards it, self-centring of the blank between these mandrelsis achieved. The pressing sleeve of a cable eye is thus always locatedentirely in the region of action of the pressing mandrels, so thatprecise, successful pressing of the cable eye and cable end is alwaysachieved. The extension element here is positioned such that a blankwhich is not positioned centrally in the pressing space is always forcedinto the desired pressing position by the extension element during thepressing process. In this case, an extension element is disposed betweentwo pressing mandrels such that the respectively facing edge of thepressing mandrel, at least in prolongation of the same, cuts across theextension element. Furthermore, the arrangement of the extension elementis selected such that the blank which is to be pressed, in an originalarrangement in the region of the lateral clearance space between twopressing mandrels, encloses an angle, between a perpendicular to thedirection in which the blank is advanced out of the clearance space anda bearing point on an oblique surface of a pressing mandrel, which islarger than the angle of friction, this achieving the desiredadvancement of the eccentrically positioned blank between the pressingmandrels during pressing. Disposing the fixed pressing mandrel on apivoting bracket which releases the pressing space advantageously makesit possible for two extension elements projecting in opposite directionsto be fitted on the fixed pressing mandrel. As a result of thisconfiguration, in the closed state of the pivoting bracket, that is tosay with the pressing space closed, extension elements disposedaccording to the invention pass through all the clearance spacesproduced between the four pressing mandrels. Irrespective of whether apressing tool with a radial pressing-space opening or a four-mandreltool with a fixed pressing mandrel fastened on a pivoting bracket ispresent, it is further proposed that an edge of the extension elementwhich is directed towards the pressing space, on the two associatedpressing mandrels, runs directly beneath the roof edge. As a result ofthis arrangement, at least in the initial state, and preferably alsoover much of the displacement path of the pressing mandrels, trapezoidalsurfaces are defined in the region of the clearance space, the top linesof these surfaces connecting the roof ridges of two adjacent pressingmandrels and the bottom lines thereof being formed by that edge of theextension element which is directed towards the pressing space. The sidelines of the trapezoidal surfaces are substantially formed by the tworoof edges of the associated pressing mandrels, the length of thetrapezium side lines corresponding to the length of a roof edge. As analternative, it is also possible for the length of this trapezium sideline to correspond to 1.1 to 1.3 times the roof-edge length. Thesignificant factor here is for the trapezium side line to be smallerthan 1.5 times the roof-edge length. In an exemplary configuration ofthe subject matter of the invention, it may be provided that anextension element is formed integrally with one pressing mandrel andmoves into a corresponding recess of the other pressing mandrel. Theextension element may thus be formed as a supplementary supportingsurface of the pressing mandrel, in which case the supplementarysupporting surfaces of two adjacent pressing mandrels overlap as theyare moved together and, in the extended state, that is to say in theinitial state, close the clearance space between the two adjacentpressing mandrels at least to the extent where a cable eye ofconventional diameter cannot pass through. In this respect, it isfurther proposed that an edge of the extension element which is directedtowards the pressing space runs into the eaves of the roof of thepressing mandrel, this edge of the extension element also being inclinedpreferably approximately to the same extent as the remote roof edge ofthe associated pressing mandrel. Furthermore, it is preferably providedthat the extent of the integrally formed extension element is less thanthe width of the roof. A preferred configuration is one in which theextent of the integrally formed extension element is less than half thewidth of the roof. It is advantageously further provided that twoadjacent pressing mandrels each have an integrally formed extensionelement, the extension elements alternately projecting towards oneanother. In this case, each extension element is assigned, laterallyadjacent to it, a recess for the introduction of the extension elementof the adjacent pressing mandrel. As a result of this configuration, itis ensured that the extension elements, which shift the blank, forexample the cable eye, into the correct position, do not enter into thepressing space. Accordingly, only the pressing mandrels with theroof-like cross-sectional profile are active during pressing. It is alsoprovided that the associated extension elements are offset depthwise inrelation to one another. As an alternative to the pressing mandrel andextension element being formed in one piece, it may also be providedthat an extension element is formed by a rod-like element which isanchored in one pressing mandrel and is accommodated in a freely movablemanner in the other pressing mandrel. For this purpose, the other,adjacent pressing mandrel has, for example, a bore into which theextension element can penetrate during the pressing operation and theaccompanying displacement of the pressing mandrels and/or of thepressing jaws carrying the latter. In this respect, it is furtherprovided that the extension element is a round rod, which mayfurthermore also be in the form of a needle. In addition, it is providedthat two rod-like extension elements are offset in relation to oneanother. These are thus, further preferably, offset depthwise inrelation to one another, so that the extension elements act in adjacentplanes. As a further alternative, it may be provided that the extensionelement is attached to a side surface of the pressing mandrel, and/or ofthe pressing jaw carrying the pressing mandrel, and moves past the sidesurface of the adjacent pressing mandrel during pressing. It is thusfurther preferably provided that two oppositely located extensionelements are fastened on a pressing mandrel. These extension elementsattached on both sides of the pressing mandrel are advantageously formedsymmetrically here, it being possible for an extension element to be inthe form of a sheet-metal angle element. As an alternative the extensionelement may also be in the form of a bent wire part.

The invention is explained in more detail hereinbelow with reference toaccompanying drawings, which merely illustrate a number of exemplaryembodiments and in which:

FIG. 1 shows, in a perspective illustration, a hydraulic implement whichis operated by an electric motor and has an associated pressing toolaccording to the invention;

FIG. 2 shows a further perspective illustration of a hydraulic implementin the form of a manually operated implement with a pressing toolaccording to the invention;

FIG. 3 shows a partially longitudinally sectioned pressing tool in theinitial state, relating to a first embodiment;

FIG. 4 shows a sectional illustration corresponding to FIG. 3, but in asection through a plane adjacent to FIG. 3;

FIG. 5 shows the pressing tool of the first embodiment in a perspectiveillustration on its own;

FIG. 6 shows the enlargement of the region VI—VI in FIG. 4;

FIG. 7 shows an illustration corresponding to FIG. 4, but relating tothe pressing position;

FIG. 8 shows an illustration corresponding to FIG. 3, but relating to asecond embodiment of the pressing tool;

FIG. 9 shows a section through a plane adjacent to FIG. 8;

FIG. 10 shows a perspective exploded illustration of the pressing toolaccording to the second embodiment;

FIG. 11 shows the enlargement of the region XI—XI in FIG. 9;

FIG. 12 shows a further enlargement, but this time relating to anintermediate position of the pressing mandrels of the pressing toolduring the pressing operation;

FIG. 13 shows an illustration corresponding to FIG. 9, but relating tothe pressing position;

FIG. 14 shows the pressing tool in partially longitudinally sectionedillustration, relating to a third embodiment;

FIG. 15 shows the longitudinal section adjacent to FIG. 14;

FIG. 16 shows the enlargement of the region XVI—XVI in FIG. 15;

FIG. 17 shows a further illustration corresponding to FIG. 3, relatingto a fourth embodiment of the pressing tool;

FIG. 18 shows the enlargement of the region XVIII—XVIII in FIG. 17;

FIG. 19 shows a perspective exploded illustration of the pressing toolaccording to FIG. 17;

FIG. 20 shows a further perspective exploded illustration of a pressingtool in a fifth embodiment;

FIG. 21 shows a sectional illustration, corresponding to FIG. 3, of apressing tool in a sixth embodiment;

FIG. 22 shows the enlargement of the region XXII—XXII in FIG. 21;

FIG. 23 shows the perspective exploded illustration of the pressing toolin FIG. 21;

FIG. 24 shows a view of a pressing tool in a seventh embodiment, with apivoting bracket retained in the open position;

FIG. 25 shows a partial sectional illustration corresponding to FIG. 3,relating to the embodiment according to FIG. 24;

FIG. 26 shows a sectional illustration of the pressing tool, the sectionplane being offset in relation to that of FIG. 25;

FIG. 27 shows the enlarged region XXVII—XXVII in FIG. 26.

A hydraulic implement 1 in the form of a pressing implement, which isoperated by an electric motor, will be illustrated and described in thefirst instance with reference to FIG. 1. Such a pressing implement isknown from German Patent Application 198 25 160.2. Reference is alsomade to German Patent Application 197 43 747. The content of thesepatent applications are hereby included in full in the disclosure of thepresent invention, also for the purpose of including features of thesepatent applications in claims of the present invention.

An electric motor is disposed in the implement 1. This electric motor isdriven via a storage battery 3 integrated in a handgrip 2. Actuation ofa finger-actuable switch 5 causes oil to be pumped from a supplycontainer into a pressure space, as a result of which a hydrauliccylinder is moved, counter to the action of a restoring spring, in thedirection of its operating end position.

The hydraulic cylinder is moved back via a restoring spring as soon as anon-return value opens on account of a predetermined maximum pressurebeing exceeded.

The implement illustrated in FIG. 2 is in the form of a manuallyactuable implement. Accordingly, the pressure required for displacingthe hydraulic cylinder is built up by manual actuation, via a pumpinglever 6, rather than by an electric motor.

Irrespective of the formation of the implement 1, the latter has a neck7 which encloses the hydraulic cylinder (not illustrated specifically)and on which a pressing tool 8 can be disposed. The arrangement of thesecuring head 9 of the pressing tool 8 on the neck 7 is preferablychosen such that the securing head 9, and thus the pressing tool 8, canbe rotated about the neck axis.

Irrespective of the embodiments described hereinbelow, the pressing tool8 substantially comprises two shell-like housing parts 10, 11 which,screw-connected to one another, leave an accommodating space betweenthem for the purpose of accommodating four pressing jaws 16 to 19 eachprovided with a pressing mandrel 12 to 15 (see, in this respect, forexample the illustration in FIG. 10).

In a known manner here, the pressing jaw 16 is mounted for slidingaction in the housing along the longitudinal extent of the pressing tool8 and has the hydraulic piston of the implement 1 acting on it from therear during the pressing operation.

Opposite the surface on which the hydraulic piston acts, the associatedpressing mandrel 12 is formed on the pressing jaw 16, disposed on thehydraulic-piston axis in the operating position. This pressing mandrel,just like the further pressing mandrels 13 to 15 which are yet to bedescribed, has a circular outline in plan view with a roof-likecross-sectional profile, the roof ridge 20 being oriented transverselyto the displacement direction of the pressing jaw.

Above and beneath the pressing mandrel 12, the pressing jaw 16 isprovided with wedge-shaped notches, the wedge surfaces 21, which aredirected away from the pressing mandrel 12, interacting withcorrespondingly oriented wedge surfaces 22 of the pressing jaws 17 and18. Rolling-contact bearings 23 are disposed between the wedge surfaces21 and 22.

Furthermore, in the region of the continuation 24 formed by the cutouts,and carrying the pressing mandrel 12, guide pins 25 which extendparallel to the wedge surfaces 21 are anchored on both sides, the otherends of these guide pins penetrating into correspondingly oriented bores26 of the pressing jaws 17 and 18. Positioned between the pressing jaws17, 18 and the continuation 24 of the pressing jaw 16 in each case is acompression spring 27, which surrounds the associated guide pin 25.

On the side which is directed away from the continuation 24 of thepressing jaw 16, furthermore, the pressing jaws 17, 18 have a controlsurface 28, which runs at right angles to their wedge surface 22 and,assisted by the compression spring 27, engages against a guide roller 29which is mounted in a rotatable manner on the housing.

The mutually facing surfaces 30, 31 of the pressing jaws 17, 18 and ofthe continuation 24—in relation to a longitudinally sectionedillustration according to FIG. 3—are oriented parallel to a displacementaxis x which runs in extension of the hydraulic-piston axis.

The pressing mandrels 13, 14 are oriented towards one another, at rightangles to the pressing mandrel 12, on the surfaces 30 of the pressingjaws 17, 18.

The fourth pressing jaw 19 is anchored in the housing, and is thusfixed, the pressing mandrel 15 thereof, oriented along the axis x,facing in the direction of the opposite pressing mandrel 12 of thedisplaceable pressing jaw 16.

In the initial state of the pressing tool 8, the pressing mandrels 12 to15 are spaced apart uniformly from one another. The pressing space 34described here is open on both sides by way of corresponding recesses 32in the housing parts 10, 11. These recesses 32 are open radiallyoutwards in the direction of an end side of the pressing tool 8, anintroduction channel 33 being formed as a result. Starting from the endside of the pressing tool 8, this introduction channel substantiallyextends between the fixed pressing mandrel 15 and a pressing mandrel 14disposed perpendicularly thereto. As a result of this configuration, itis possible for a cable end which is to be pressed, for example, with acable eye to be introduced through the introduction channel 33 into thepressing space 34 bounded by the pressing mandrels 12 to 15.

During a pressing operation, in the case of which the hydraulic pistonof the implement 1 engages against the rear of the pressing jaw 16, thispressing jaw 16 with the pressing mandrel 12 is displaced, along thepressing axis x, in the direction of the fixed pressing mandrel 15located opposite, which at the same time, via the wedge surfaces 21 and22—with the roller-contact bearings provided therebetween—and via thecontrol surface 28 supported on the guide roller 29, causes the pressingjaws 17 and 18 to be displaced. This displacement of the pressing jaws17, 18 takes place both parallel to the displacement of the pressing jaw16 and, at the same time, in the perpendicular direction, so that thethree movable pressing mandrels 12 to 14 move uniformly in the directionof the fixed pressing mandrel 15, with the blank, for example cable eye35, which is positioned in the pressing space 34 being pressed uniformlyin the process.

Once pressing has taken place, that is to say once a predeterminedpressing pressure has been exceeded, the hydraulic piston, as has beendescribed, moves back automatically into the starting position. Thepressing jaws follow the hydraulic piston on account of the compressionsprings 27, which are compressed during pressing, being relieved ofstressing, the pressing jaws 17, 18 being carried along via the guidepins 25 anchored in the pressing jaw 16.

In order for the cable eye 35 which is to be pressed, and is positionedin the pressing space 34, to be prevented from sliding into the lateralclearance spaces 36 which are located between the pressing mandrels andare increasingly reduced during the pressing operation—which slidingaction could possibly result in unsuccessful pressing—various solutionsare presented by the embodiments which are described in more detailhereinbelow.

Common to all the embodiments illustrated is the fact that two pressingmandrels 12 and 13, 12 and 14 and also 13 and 15 have disposed betweenthem in each case an extension element 37 which extends from onepressing mandrel to the other, the extension element 37 being anchoredon one pressing mandrel and moving into the other pressing mandrelduring pressing. According to the invention, the extension elements 37,for the purpose of blocking the clearance space 36, are disposed suchthat, both in the initial state and during the pressing operation, thetwo associated roof edges 38 of the pressing mandrels bounding theclearance space 36 cut across the extension element 37, it being thecase, furthermore, that the edge 39 of the extension element 37 which isdirected towards the pressing space 34, on the two associated pressingmandrels, runs directly beneath the roof edge 38. This results in theformation of a trapezoidal surface T which is bounded by the facingedges 38 of the associated pressing mandrels and that edge of theextension element 37 which is directed towards the pressing space 34 andalso by an imaginary line connecting the roof ridges 20 of theassociated pressing mandrels, the side boundary lines of the trapezoidalsurface corresponding to 1 to 1.3 times the roof-edge length. As aresult of this configuration, the blank, for example the cable eye 35,is always forced in the direction of the pressing space 34 during thepressing operation, that is to say during the advancement of thepressing mandrels 12 to 14 in the direction of the pressing mandrel 15,so that the blank is present in the correct position between thepressing mandrels 12 to 15 during pressing.

In the first exemplary embodiment, which is illustrated in FIGS. 3 to 7,the extension element 37 is formed integrally with a pressing mandrel 12to 15, in order to form a supplementary supporting surface. Eachpressing mandrel 12 to 15 has a protrusion-like extension element 37 ineach case assigned to each roof edge 38, the two extension elements 37of a pressing mandrel being disposed in offset planes in the directionin which the roof ridge 20 extends. Recesses 40 are provided on one sideadjacent to these extension elements 37, extension elements 37 of theadjacent pressing mandrels moving into these recesses during thepressing operation, and the extension elements 37 of two adjacentpressing mandrels projecting alternately towards one another in eachcase.

The edge 39 of the integrally formed extension element 37, this edgebeing directed towards the pressing space 34, runs approximatelyparallel to the remote roof edge 38 of the associated pressing mandrel,this edge 39 furthermore running into the eaves 41 of the roof of thefacing roof edge 38 of the pressing mandrel (see FIG. 6).

The extension elements 37, which overlap when the pressing mandrels aremoved together, close the clearance space 36, which is formed betweenthe pressing mandrels, to the extent where the conventional-diameterblank cannot pass between the extension elements 37 into the clearancespace 36. The extent a of the integrally formed extension element 37 isthus selected to be less than half the width b of the pressing-mandrelroof.

As an alternative, the extension element 37 may be formed in a rod-likemanner as a round rod 42 (see second embodiment in FIGS. 8 to 13) or asa needle 43 (see third embodiment in FIGS. 14 to 16). These rod-likeextension elements 37—round rod 42 or needle 43—are anchored in one ofthe pressing mandrels and accommodated in a freely movable manner in theother associated pressing mandrel.

It is thus the case in the third and fourth exemplary embodimentsillustrated that two rod-like extension elements 37 projecting inopposite directions are anchored in the continuation 24, which carriesthe pressing mandrel 12. These extension elements each pass through theadjacent clearance space 36 and penetrate into correspondingly formedguide bores 44 of the pressing jaws 17 and 18, which carry the pressingmandrels 13 and 14, respectively. Here too, the extension elements 38are offset depthwise in relation to one another, that is to say they aredisposed in offset planes.

Furthermore, a rod-like extension element 37 is anchored in the fixedpressing jaw 19, which carries the pressing mandrel 15, this extensionelement likewise penetrating into a guide bore 44 of the pressing jaw17, which carries the pressing mandrel 13, and blocks the adjacentclearance space 36 in the operation.

In the second embodiment illustrated according to FIGS. 8 to 13, thediameter of the guide bores 44 corresponds to the diameter of the roundrod 42 forming the extension element 37. In contrast, in the thirdexemplary embodiment, which is illustrated in FIGS. 14 to 16, thediameter of the needle 43 forming the extension element 37 isconsiderably smaller than the diameter of the guide bore 44, for whichpurpose the needle 43 has a sliding head 45 arranged, for guidancepurposes, in the region of the guide bore 44.

Disposing the rod-like extension elements 37 directly beneath the roofedges 38 results in the cable eye 35 which is to be pressed enclosing anangle alpha, between a perpendicular S to the advancement direction u ofthe cable eye 35 and a bearing point P on a roof edge 38, which islarger than the angle of friction, this achieving the desiredadvancement of the eccentrically positioned cable eye 35 between thepressing mandrels during pressing. An angle alpha of 15 degrees isprovided in the exemplary embodiment illustrated (see FIG. 12).

As can further be gathered from the drawings of FIGS. 17 to 20, whichillustrate a fourth and a fifth embodiment, the extension elements 37may also be in the form of bent wire parts 46 which are disposedlaterally opposite one another on the pressing mandrel 12 or pressingjaw 16 and the angled free legs of which block the clearance spaces 36between the pressing mandrel 12 and the pressing mandrel 13 and betweenthe pressing mandrel 12 and the pressing mandrel 14, as a result ofwhich the blank is always forced into the correct pressing position bythe wire legs. The sectional illustration in FIG. 17 shows anintermediate position during the pressing operation.

Furthermore, according to the sixth embodiment, the extension element 37may be in the form of a sheet-metal angle element 47, these likewisebeing disposed opposite one another on both sides of the pressingmandrel 12 or of the pressing jaw 16 and, in the same way as thepreviously described bent wire parts 46, having symmetrically formedlegs for forming the extension elements 37.

Finally, FIGS. 24 to 27 show a seventh embodiment, in the case of whichthe fixed pressing mandrel 15, and the pressing jaw 19 thereof, isfastened on a pivoting bracket 48, which is mounted in a pivotablemanner on the housing and by means of which the radial access to thepressure space 34 can be blocked. For this purpose, the housing parts 10and 11 have an approximately U-shaped outline in plan view, theU-opening forming the pressing space 34. The pivoting bracket 48 ismounted on one U-leg such that it can be rotated about an axis y. Theother, free end of the pivoting bracket 48 can be latched in the regionof the opposite U-leg of the housing, it being possible for thislatching action to be cancelled by means of a handle 49 (not illustratedspecifically).

Fitted on the fixed pressing mandrel 15, which is fastened on thepivoting bracket 48, are two extension elements 37 in the form of roundrods 42, which project in opposite directions and, in the closed stateof the pressing tool 8 according to FIGS. 25 and 26, penetrate intocorrespondingly associated guide bores 44 of the adjacent pressingmandrels 13, 14. The pressing space 34, which is fully enclosed by apivoting bracket 48 being provided according to the invention, issurrounded, then, by four extension elements 37 which block all theclearance spaces 36 formed between the pressing mandrels.

All features disclosed are (in themselves) pertinent to the invention.The disclosure content of the associated/attached priority documents(copy of the prior application) is hereby also included in full in thedisclosure of the application, also for the purpose of incorporatingfeatures of these documents in claims of the present application.

1. A pressing tool with three or four pressing mandrels for pressing aworkpiece which can be moved towards one another during a pressingoperation, each pressing mandrel having a roof-like cross-sectionalprofile which defines first and second roof edges which meet at a roofridge, said first roof edges of each said pressing mandrel generallyface said second roof edges of an adjacent pressing mandrel, and thus,furthermore, a lateral clearance space between the pressing mandrels isincreasingly reduced during a pressing process, and disposed between twopressing mandrels is an extension element for engaging a workpiece whichextends from one pressing mandrel to the other and moves into the otherpressing mandrel during pressing, wherein the extension element, for thepurpose of blocking the clearance space, is disposed such that, in theinitial state and during pressing, the respectively facing first andsecond roof edges of the two pressing mandrels having the extensionelement disposed therebetween, cut across the extension element.
 2. Apressing tool according to claim 1, wherein one pressing mandrel isfixed and the three further pressing mandrels can be displaced in thedirection of a center of a pressing space during a pressing operation,wherein the fixed pressing mandrel is fastened on a pivoting bracket, bymeans of which radial access to the pressing space can be blocked.
 3. Apressing tool according to claim 2 wherein two extension elementsprojecting in opposite directions are fitted on the fixed pressingmandrel.
 4. A pressing tool according to claim 2, wherein an edge of theextension element which is directed towards the pressing space, runsdirectly beneath the respectively facing first and second roof edges ofthe two pressing mandrels having the extension element disposedtherebetween.
 5. A pressing tool according to claim 1, wherein anextension element is formed integrally with one pressing mandrel andmoves into a corresponding recess of the other pressing mandrel.
 6. Apressing tool according to claim 5, wherein said first and second roofedges of each said pressing mandrel define eaves opposite said roofridge, and wherein an edge of the extension element which is directedtowards the pressing space runs into the eaves of one of the first andsecond roof edges.
 7. A pressing tool according to claim 6, wherein anextent of the integrally formed extension element is less than a widthof the first and second roof edges, said width of the first and secondroof edges being defined as a distance from the eaves of the first roofedge to the eaves of the second roof edge.
 8. A pressing tool accordingto claim 6, wherein an extent of the integrally formed extension elementis less than half a width of the first and second roof edges, said widthof the first and second roof edges being defined as a distance from theeaves of the first roof edge to the eaves of the second roof edge.
 9. Apressing tool according to claim 1, wherein two adjacent pressingmandrels each have an extension element formed thereon, the extensionelements alternately projecting towards one another.
 10. A pressing toolaccording to claim 9, wherein the extension elements are offsetdepthwise in relation to one another.
 11. A pressing tool according toclaim 1, wherein the extension element is formed by a rod-like elementwhich is anchored in one pressing mandrel and is accommodated in afreely movable manner in the other pressing mandrel.
 12. A pressing toolaccording to claim 1, wherein the extension element is a round rod. 13.A pressing tool according to claim 1, further including two rod-likeextension elements offset in relation to one another.
 14. A pressingtool according to claim 1, wherein the extension element is attached toa side surface of one of the pressing mandrels and moves past a sidesurface of one of the adjacent pressing mandrels during pressing.
 15. Apressing tool according to claim 1, further including two oppositelylocated extension elements fastened on one of said pressing mandrels.16. A pressing tool according to claim 1, wherein the extension elementis in the form of a sheet-metal angle element.
 17. A pressing toolaccording to claim 1, wherein the extension element is in the form of abent wire part.